There is a general need in the art for boat hull designs which provide reasonable combinations of efficiency, speed, displacement and length. Such boats hulls have practical applications for boats adapted for personal cruising and for fishing, among others.
General information regarding boat hull architecture is set forth in the three volume" Principles of Naval Architecture," Edward V. Lewis, ed., 2d rev. 1988, published by the Society of Naval Architects and Marine Engineers (hereinafter "PONA"). PONA does not cover trimaran hulls. Moreover, the discussion of catamaran concepts is restricted to slender planing hulls. While this reference sets forth information regarding slender monohull boats, such as destroyers and other "fast" displacement monohull boats, the data mostly covers speeds corresponding to Froude numbers (F.sub.N) up to 0.45-0.60. Data on displacement hulls corresponding to Froude numbers in the range of 1.0-1.5 are included for the Series 64 model test data (F.sub.N =1 for a 48' boat at a speed of 27 statute miles per hour). It appears that the Series 64 models generally go to extremes in reducing wave making resistance at the expense of increased friction resistance. Also, length to displacement ratios for the Series 64 models indicated reduced utility and practical application for full scale boats. See PONA, vol. II, pp. 95-98.
Existing art for power boats typically includes a single rigid hull; such boats are referred to as "monohull" vessels. Typically, the hulls of such vessels have either a deeply V-shaped cross section, which cuts deeply into the water and provides a relatively smooth ride through the water at the cost of high fuel consumption, or they have a flatter hull configuration that allows the vessel to plane, thereby reducing fuel consumption while providing a less smooth ride.
Existing art for boats also includes vessels constructed with two, three, or more hulls. These boats are referred to as catamarans, trimarans, or generally as multihull vessels. Multihull vessels have the advantage of more lateral stability than a monohull vessel, but with a wetted surface area that is normally higher than that of a monohull vessel of similar size.
There have been various attempts to overcome disadvantages of the existing art and to take advantage of certain features of multihulled vessels. For example, U.S. Pat. No. 4,494,477 to Matthews discloses a vessel that is capable of adjustment so as to be either a monohull vessel or a multihull vessel. The vessel includes means for moving portions of the hull so as to provide variable characteristics between monohull and multihull. The invention does not describe a solely trimaran-type vessel--one absent the additional features for variable hull adjustment--nor does Matthews provide a method for designing a vessel so as to account for the variable factors involved in trimaran operation.
U.S. Pat. No. 5,107,783 to Magazzu describes a generally monohulled vessel with twin adjustable side floats, which provides some features of a trimaran. Magazzu does not provide a solely fixed trimaran design nor a method for designing a vessel so as to account for the variable factors involved in trimaran operation.
U.S. Pat. No. 5,178,085 to Hsu describes a multihull vessel with slender hulls for wave cancellation. Hsu does not provide a method for designing a vessel so as to account for the variable factors involved in trimaran operation, including variabilities in size of boats and hulls.
U.S. Pat. No. 5,191,849 to Labrucherie, et al., provides for a multihulled boat with at least three hulls that utilizes the compressive force of air between hulls to lift the boat during operation. Labrucherie does not provide a method for designing a vessel so as to account for the variable factors involved in trimaran operation, including variabilities in size of boats and hulls.
U.S. Pat. No. 5,265,554 to Meredith describes a multihulled vessel with ski-like chines the provide additional lift to the vessel during operation. Meredith does not provide a method for designing a vessel so as to account for the variable factors involved in trimaran operation, including variabilities in size of boats and hulls.
U.S. Pat. No. 5,269,245 to Bystedt, et al., provides an onion-shaped cross-section multihull design structure using a split front to rear design that has variable characteristics that depend on boat speed. Bystedt does not provide a method for designing a vessel so as to account for the variable factors involved in trimaran operation, including variabilities in size of boats and hulls.
U.S. Pat. No. 5,529,009 to Faury describes a boat multihull design for a large ship based on the surface area of hull floats, the weight of the ship, and a formula involving the distance from the center of displacement to the center of gravity of the ship. Faury does not provide a generalized method for designing a vessel so as to account for the variable factors involved in trimaran operation, including variabilities in size of boats and hulls.
U.S. Pat. No. 5,237,947 to Manning and U.S. Pat. No. 5,325,804 to Schneider, generally describe vessels with outboard submersible extensions, which are distinguishable from fixed non-submersible hulled trimarans in both function and operation.
Other relevant sources of information about the existing art include the following: 1) "Principles of Naval Architecture Second Edition", Edited by Edward V. Lewis, The Society of Naval Architects and Marine Engineers (1988); 2) Dave Gerr, "Propeller Handbook", International Marine, A Division of the McGraw Hill Companies, (1988); 3) Lars Larsson and Rolf E. Eliason, "Principles of Yacht Design," International Marine, A Division of the McGraw Hill Companies (1994); 4) Captain Robert P. Beebe, Revised by James F. Leisaman, "Voyaging Under Power," International Marine, A Division of the McGraw Hill Companies (1994); 5) "Jane's Fighting Ships 1996-1997," Ninety-Ninth Edition, Edited by Captain Richard Sharpe RN (1996); 6) Chuck Paine, "Nordhavn 57," Yachting Magazine, 37 (August 1996); 7) George L. Petrie, "Capri-Craft 532 Catamaran," Power and Motoryacht Magazine, 38 (November 1996); 8) Captain Jim Gorant, "East to East," Power and Motoryacht Magazine, 120 (November 1996); 9) Captain Ken Kreisler, "Just Launched, Hinkley 67," Power and Motoryacht Magazine, 26 (October 1996); 10) "All the New Boats," Motorboating and Sailing Magazine, 40-76 (January 1995).